The application of image processing technology to biology has given rise to the Normalized Difference Vegetative Index (NDVI). The NDVI is a commonly used metric for identifying plant growth within an image and relies on plant chlorophyll strongly absorbing visible red wavelengths, while reflecting green wavelengths. The NDVI metric is sometimes formulated as:
  NDVI  =                    r        NIR            -              r        VIS                            r        NIR            +              r        VIS            where rVIS and rNIR are the spectral reflectance measurements acquired in the red visible and near-infrared regions, respectively.
The NDVI can be a useful tool for crop growers, e.g., it can help to determine when and how much fertilizer to apply. However, the application of the NDVI equation and other variants has been specific to vegetation. Further developments in image processing techniques will further assist crop growers and other individuals and organizations involved with land management and valuation.